Background: Left ventricular (LV) outflow tract (LVOT) obstruction
increases mortality in patients undergoing transcatheter mitral valve
implantation (TMVI) in degenerated bioprostheses, annuloplasty rings,
and native mitral valves. We aimed to evaluate the left ventricular
outflow tract area after TMVI using 3-diensional (3D) transesophageal
echocardiography (TEE) and to investigate the pre-procedural cardiac
geometry affects the LVOT area after TMVI. Methods: We retrospectively
reviewed echocardiography data in 43 patients who had TMVI. A change in
pressure gradient across LVOT from before to after TMVI (∆PG) and
post-procedure 3D cross sectional area (CSA) at the level of the most
distal portion of the mitral valve stent that was closest to the LV apex
were assessed as evidence of LVOT narrowing. Results: TMVI with the use
of balloon-expandable valve system was performed for 24 bioprostheses, 7
annuloplasty rings, and 12 native valves. Compared to patients without
increase in LVOT gradient (∆PG <10 mmHg; n=33), patients with
increase in LVOT gradient (∆PG ≥10 mmHg; n=10) had smaller LV
end-systolic volume (LVESV), greater LV ejection fraction (LVEF) and
smaller aorto-mitral (AM) angle. CSA at the valve stent distal edge
showed strong association with ∆PG (r=-0.68, P<0.0001). Only
small AM angle was associated with small CSA at the valve stent
ventricular edge on multivariable analysis, independent of LVESV and
LVEF. Conclusion: Pre-procedural AM angle as well as LVESV and LVEF were
associated with LVOT narrowing in patients undergoing transcatheter
mitral valve-in-valve, valve-in-ring, and valve-in-native valve
implantation. These data may be useful for preprocedural planning.
Role of Perioperative TEE in Diagnosing and Management of a Case of Dynamic LVOT Obstruction/SAM